Reasons for non-intensification of treatment in people with type 2 diabetes receiving oral monotherapy: Outcomes from the prospective DIAttitude study

Objectives

To describe the management of glucose-lowering agents in people with type 2 diabetes initially on oral monotherapy, cared for by French general practitioners, and to identify reasons underlying treatment non-intensification.

Methods

People with type 2 diabetes on oral monotherapy were recruited by general practitioners and followed-up over 12 months. Patient characteristics, HbA1c, and glucose-lowering treatments were recorded electronically. Management objectives and reasons for treatment non-intensification were solicited from the general practitioners.

Results

A total of 1212 patients were enrolled by 198 general practitioners; 937 patients (mean age 68 years) were treated with oral monotherapy, and 916 patients had at least two successive HbA1c values recorded. Of these, 390 patients (43%) had HbA1c ≥ 6.5% on both occasions, and 164/390 (42%) had their treatment intensified. The 226 patients whose treatment was not intensified were older (69 ± 11 years vs. 66 ± 12 years, P = 0.02) and had better glycaemic control at study inclusion (6.9% ± 0.6 vs. 7.3% ± 0.8, P < 0.0001) than treatment intensified patients. Among uncontrolled patients, there were no differences in general practitioner treatment objectives at inclusion for treatment intensified and non-intensified patients; the main reason given by general practitioners for non-intensification was that the patient had an adequate HbA1c (66%). HbA1c did exceed the 6.5% target, but was less than 7.0% in 69% of cases.

Conclusions

General practitioners showed a patient-centred approach to treatment, but clinical inertia was apparent for 31% of the uncontrolled patients.     

Asymmetrical dimethylarginine is related to renal function, chronic inflammation and macroangiopathy in patients with Type 2 diabetes and albuminuria.

AIMS: Patients with Type 2 diabetes mellitus (T2DM) and micro- and macroalbuminuria are at increased cardiovascular risk. The endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) is increased in renal failure and could promote atherosclerosis. To determine the relationship between ADMA, renal albumin excretion rate (AER) and cardiovascular risk, we studied 103 T2DM patients. METHODS: ADMA, symmetrical dimethylarginine (SDMA) and L-arginine were determined by high-performance liquid chromatography in plasma from 36 normo-, 40 micro- and 27 macroalbuminuric patients with T2DM (age 64 +/- 11 years; 38 women) who had comparable age, sex and metabolic parameters. Forty-six patients had macrovascular disease (MVD). RESULTS: ADMA was significantly increased in patients with micro- and macroalbuminuria [median 0.61 (interquartile range 0.55-0.70) micromol/l and 0.62 (0.50-0.79) micromol/l, respectively] compared with those with normoalbuminuria [0.55 (0.48-0.63) micromol/l; both P < 0.05]. SDMA was elevated in micro- and macroalbuminuria [0.57 (0.42-0.80) micromol/l and 0.64 (0.50-0.96) micromol/l] compared with normoalbuminuric subjects [0.44 (0.37-0.53) micromol/l; both P < 0.01]. Patients with increased AER and MVD had higher ADMA and SDMA compared with those without MVD (both P < 0.001). L-arginine was comparable between all groups. ADMA correlated significantly with high-sensitivity C-reactive protein (hsCRP) and glomerular filtration rate (GFR) but not with the extent of albumin excretion, body mass index, fasting glucose, HbA(1c) or plasma lipids. CONCLUSIONS: Increased ADMA in T2DM patients with albuminuria is linked to cardiovascular disease and is associated with renal dysfunction and subclinical inflammation.     

Comparable efficacy of self-monitoring of quantitative urine glucose with self-monitoring of blood glucose on glycaemic control in non-insulin-treated type 2 diabetes

Aim

To assess whether self-monitoring of quantitative urine glucose or blood glucose is effective, convenient and safe for glycaemic control in non-insulin treated type 2 diabetes.

Methods

Adults with non-insulin treated type 2 diabetes were recruited and randomized into three groups: Group A, self-monitoring with a quantitative urine glucose meter (n = 38); Group B, selfmonitoring with a blood glucose meter (n = 35); Group C, the control group without selfmonitoring (n = 35). All patients were followed up for six months, during which identical diabetes care was provided.

Results

There was a significant decrease in HbA1c within each group (p < 0.05). At the study conclusion, mean changes in HbA1c from baseline were −1.9% for Group A, −1.5% for Group B and −1.0% for Group C, and the proportion of patients achieving HbA1c≤6.5% were 38.9%, 35.3% and 20.0% respectively. However, no significant differences between the groups were found. The average monitoring frequency was significantly higher in Group A than in Group B. The incidence of hypoglycaemia and quality of life scores were similar between the groups.

Conclusions

This study suggests that self-monitoring of urine glucose has comparable efficacy on glycaemic control, and facilitates better compliance than blood self monitoring, without influencing the quality of life or risk of hypoglycaemia.     

L-Arginine Pathway in COPD Patients with Acute Exacerbation: A New Potential Biomarker

Background: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) remains a major cause of mortality. Clinical criteria of AECOPD are subjective. Biomarkers for AECOPD may aid in the initiation of early treatment. Increased production of asymmetric and symmetric dimethylarginine (ADMA, SDMA) is related to hypoxia. In COPD, a rise in ADMA results in a shift of L-arginine breakdown, contributing to airway obstruction. We aimed to compare serum levels of ADMA, SDMA and L-arginine in patients with and without AECOPD.

Methods: L-arginine metabolites quantified by high-performance liquid chromatography in venous blood samples and partial capillary oxygen pressure were prospectively investigated in 32 patients with COPD, 12 with AECOPD and 30 healthy subjects.

Results: Both ADMA and SDMA were significantly higher in AECOPD compared to stable COPD (p = 0.004 and p < 0.001, respectively). Oxygen content in capillaries correlated with serum ADMA concentration. However, the concentration of L-arginine was not different between AECOPD and stable COPD. Both ADMA and SDMA separated AECOPD with high sensitivity and specificity (AUC: 0.81, p = 0.001; AUC: 0.91, p < 0.001, respectively). A cut-off value ≥0.57 for SDMA was an independent variable to confirm AECOPD in a regression model (OR: 1.632, p = 0.001). All markers were significantly higher in the sera of both patient groups compared to the controls (p < 0.05, respectively).

Conclusions: COPD is associated with elevated L-arginine, ADMA and SDMA serum levels. In patients with AECOPD, production of ADMA and SDMA are more pronounced presumably due to more severe hypoxic insult. Methylated arginine derivatives in the sera may help early recognition of AECOPD.     

The biological effect of pharmacological treatment on dimethylaminohydrolases (DDAH-1) and cationic amino acid transporter-1 (CAT-1) expression in patients with acute congestive heart failure

Aim

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) which plays an important role in controlling vascular tone and regulates the contractile properties of cardiac myocytes. The aim of this study was to investigate the effect of pharmacological treatment on symmetric dimethylarginine (SDMA), ADMA and arginine plasma concentrations in patients with acute congestive heart failure (ACHF) through the evaluation of type-1 system cationic amino acid transporter-1/type 1 dimethylarginine dimethylaminohydrolases-1 (CAT-1/DDAH-1).

Methods and results

25 hospitalized cardiology patients with symptomatic acute congestive HF (NYHA Class III-IV) and impaired left ventricular (LV) function (ejection fraction < 35%) were included in the study. ADMA, SDMA, and arginine plasma concentrations were assessed before and after pharmacological treatment by high performance liquid chromatography. All patients received an adequate pharmacological treatment for ACHF. ADMA and SDMA plasma levels were significantly higher after pharmacological treatment respect to baseline values (pre-treatment) (0.75 vs 0.48; 1.31 vs 1.03; p < 0.01). Arginine plasma concentration was significantly lower after therapy respect to baseline values (0.78 vs 0.99; p < 0.01). This is associated more with the modulation of DDAH-1 protein than with of CAT-1 system transport.

Conclusions

In patients with ACHF, acute renal impairment function and the modulation of metabolism and extracellular transport by the DDAH-1/CAT-1 system determine high ADMA and SDMA levels after therapy for acute congestive heart failure.     

Serum asymmetric dimethylarginine levels in diabetic patients with neuropathy

Objective

The goal of our study was to evaluate the role of asymmetric dimethylarginine (ADMA) in patients with diabetic neuropathy.

Materials and methods

In this study, 58 diabetic patients and 26 healthy volunteers were included. In both groups ADMA measurements were performed together with other biochemical examinations. Nerve conduction studies and Neuropathy Symptom Score (NSS) were administered to the diabetic patients.

Results

ADMA levels were found significantly higher in diabetic patients compared to the control group (p = 0.0001). However, ADMA levels were not statistically significant between diabetic patients with neuropathy and without neuropathy (p = 0.86 and p = 0.47).

Conclusion

These results demonstrate that there is not any significant relationship between ADMA and diabetic neuropathy.     

Endogenous nitric oxide synthase inhibitors in sickle cell disease: abnormal levels and correlations with pulmonary hypertension, desaturation, haemolysis, organ dysfunction and death

Pulmonary hypertension (PH) in patients with sickle cell disease (SCD) is linked to intravascular haemolysis, impaired nitric oxide bioavailability, renal dysfunction, and early mortality. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthases (NOS), is associated with vascular disease in other populations. We determined the plasma concentrations for several key arginine metabolites and their relationships to clinical variables in 177 patients with SCD and 29 control subjects: ADMA, symmetric dimethylarginine (SDMA), NG-monomethyl L-arginine (L-NMMA), N-omega-hydroxy-L-arginine (NOHA), arginine and citrulline. The median ADMA was significantly higher in SCD than controls (0·94  μmol/l vs. 0·31 μmol/l, P  <   0·001). Patients with homozygous SCD had a remarkably lower ratio of arginine to ADMA (50 μmol/l vs. 237, P  < 0·001). ADMA correlated with markers of haemolysis, low oxygen saturation and soluble adhesion molecules. PH was associated with high levels of ADMA and related metabolites. Higher ADMA level was associated with early mortality, remaining significant in a multivariate analysis. Subjects with homozygous SCD have high systemic levels of ADMA, associated with PH and early death, implicating ADMA as a functional NOS inhibitor in these patients. These defects and others converge on the nitric oxide pathway in homozygous SCD with vasculopathy.     

Plasma asymmetric dimethylarginine predicts death and major adverse cardiovascular events in individuals referred for coronary angiography

Background

Elevated plasma level of asymmetric dimethylarginine (ADMA) was reported to be associated with endothelial dysfunction and atherosclerotic risk factors. We assessed the prognostic value of plasma ADMA levels in 997 consecutive individuals referred for coronary angiography from July 2006 to June 2009.

Methods

ADMA was measured by high performance liquid chromatography. All subjects were followed for a median period of 2.4 years for the occurrence of all-cause mortality, major adverse cardiovascular events (MACE, defined as cardiovascular death, non-fatal myocardial infarction and stroke), and MACE plus clinically-driven target vessel revascularization (TVR).

Results

Plasma ADMA levels were significantly higher in patients with significant coronary artery disease (CAD) (≥ 50% stenosis, n = 655) than those with insignificant CAD (20-50% stenosis, n = 272) and normal coronary artery (< 20% stenosis, n = 70) (0.47 ± 0.10 μmol/l vs 0.44 ± 0.10 μmol/l vs 0.42 ± 0.08 μmol/l, p < 0.001). By multivariate analysis, plasma ADMA level was identified as a significant independent risk factor of significant CAD (OR: 1.29, 95% CI: 1.10−1.50; p = 0.002). Moreover, multivariate Cox regression analysis showed that, comparing with the ADMA tertile I, the highest ADMA tertile was a significant independent predictor for all adverse long-term clinical outcomes. Notably, plasma ADMA level remained associated with the long-term outcomes in non-diabetic individuals, but not in those with diabetes (interaction p = 0.04 for MACE plus TVR).

Conclusions

Our findings suggest that elevated plasma ADMA level might be a risk factor of significant CAD, and might predict worse long-term clinical outcomes in subjects referred for cardiac catheterization, especially in non-diabetic individuals.     

Starting or switching to biphasic insulin aspart 30 (BIAsp 30) in type 2 diabetes: a multicenter, observational, primary care study conducted in Finland

Aims

Assess safety and glycaemic control in patients initiating insulin with, or switching from basal insulin to, biphasic insulin aspart 30/70 (BIAsp 30) in primary care in Finland.

Methods

A non-randomised, non-interventional, open-label, 26-week study of type 2 diabetes (T2D) patients prescribed BIAsp 30 by their physician, who determined starting dose, titration and injection frequency.

Results

496 patients provided safety data (insulin-naïve n = 197; prior insulin n = 299 [84.9% received NPH insulin]). Three patients (0.6%) reported four SADRs (three hypoglycaemia, one hypoglycaemia with unconsciousness). HbA1c was significantly (p < 0.0001) reduced after 26 weeks’ BIAsp 30 therapy (final dose): insulin-naïve −1.4% (44.4 IU); prior insulin −1.1% (77.4 IU). HbA1c < 7.0% was achieved by 10% of insulin-naïve patients at baseline and 51% at 26-week follow-up. In the prior insulin group, 7% and 30% of patients had HbA1c < 7.0% at baseline and 26 weeks, respectively. Minor hypoglycaemia increased significantly from baseline to study end: insulin-naïve 0.66-6.45 events/patient/year (p < 0.0001); prior insulin 5.11-8.58 events/patient/year (p < 0.05). Weight increased by 1.0 kg (insulin-naïve) and 1.3 kg (previous insulin).

Conclusion

BIAsp 30, initiated and titrated in T2D patients in primary care in Finland, showed a good safety profile and significantly improved glycaemic control.     

The impact of rapid atrial pacing on ADMA and endothelial NOS

Background

The endothelial nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a well-established risk factor for oxidative stress, vascular dysfunction, and congestive heart failure. The aim of the present study was to determine the impact of rapid atrial pacing (RAP) on ADMA levels and eNOS expression.

Methods and results

ADMA levels were studied in 60 age- and gender-matched patients. Thirty five patients had persistent atrial fibrillation (AF) ≥ 4 months. In AF-patients, parameters were studied before and 24 h after electrical cardioversion. Moreover, ADMA, eNOS expression, and calcium-handling proteins were studied in pigs subjected to RAP as well as in endothelial cell (EC) cultures. ADMA level was significantly higher in AF compared to sinus rhythm patients (p = 0.024). ADMA was highest in AF-patients, who also showed elevated troponin T (TnT) levels. Moreover, ADMA showed a significant linear correlation to TnT (r = 0.47; p < 0.01). After electrical cardioversion ADMA returned to normal within 24 h. In pigs, RAP for 7 h increased ADMA levels (p = 0.018) and TnI (p < 0.05), and reduced mRNA expression of ventricular and aortic eNOS (− 80%; p < 0.05) compared to sham-control. However, ADMA per se did not affect eNOS mRNA level in EC cultures.

Conclusion

The current study shows that acute and persistent episodes of atrial tachyarrhythmia are associated with elevated ADMA levels accompanied by increased ischemic myocardial markers. Moreover, RAP increases ADMA and down-regulates eNOS expression in an ADMA-independent manner. We conclude that the combination of these two separate and potentially synergistic mechanisms may contribute to long-term vascular injury during atrial tachyarrhythmia.     

Elevated concentrations of asymmetric dimethylarginine are associated with deterioration of glucose tolerance in women with previous gestational diabetes mellitus

OBJECTIVE: Women with previous gestational diabetes mellitus (GDM) have a high risk for development of type 2 diabetes mellitus. The endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) could be related to disorders of the glucose metabolism. To evaluate if ADMA predicts deterioration of glucose tolerance in women with previous GDM and to assess concentration changes we analysed ADMA in women with previous GDM after delivery and after a median follow-up of 2.75 years (interquartile range: 1.47-4.60). DESIGN: Prospective cohort study. Subjects and methods. ADMA, symmetric dimethylarginine (SDMA) and L-arginine were determined in 77 women with previous GDM who underwent a 75-g oral glucose tolerance test 4 months after delivery and at follow-up. RESULTS: Deterioration in glucose tolerance was observed in 36% of the women with ADMA above and 11% of those with ADMA below the median (0.56 micromol L(-1); P = 0.008, log-rank test). ADMA correlated significantly with mean arterial blood pressure and nonsignificantly with body mass index (P = 0.050) but not with insulin resistance, fasting glucose, lipids or glomerular filtration rate. The fully adjusted hazard ratio for a decline of glucose tolerance during follow-up was 3.94 (95% CI: 1.16-13.37; P = 0.028) for subjects with ADMA above the median. SDMA and L-arginine were not associated with changes in the glucose tolerance status. ADMA and L-arginine decreased significantly during follow-up. CONCLUSIONS: High serum ADMA after delivery is associated with deterioration in glucose tolerance in women with previous GDM and declines in the following years.     

Evaluation of Asymmetric Dimethylarginine (ADMA) Levels in Children with Growth Hormone Deficiency

Ob­jec­ti­ve: To investigate serum asymmetric dimethylarginine (ADMA) levels in children with isolated growth hormone deficiency (GHD) and to determine the effect of GH replacement therapy on these levels.Methods: 31 patients diagnosed with isolated GHD and 29 age-and sex-matched healthy children were enrolled in the study. Height, weight and waist circumference were measured in all subjects. Fasting serum insulin-like growth factor-1 (IGF-1), IGF binding protein-3, glucose, insulin and lipid levels were evaluated. Serum ADMA levels were assessed using the enzyme-linked immunosorbent assay technique. The same evaluations were repeated on the 3^rd and 6^th months of treatment in 28 of the GHD cases.Results: There were no significant differences in ADMA levels between the patient and control groups [0.513±0.130 (0.291-0.820) µmol/L vs. 0.573±0.199 (0.241-1.049) µmol/L]. There was a positive correlation between serum ADMA and HbA1c levels in the control group. In the GHD cases, ADMA levels negatively correlated with high-density lipoprotein levels and positively correlated with low-density lipoprotein levels. There was also a significant increase in ADMA levels in patients receiving GH therapy compared to pre-treatment levels [serum ADMA level, 1.075±0.133 (0.796-1.303) µmol/L at the 3rd month and 0.923±0.121 (0.695-1.159) µmol/L at the 6th month of treatment]. There was a negative correlation between ADMA levels and homeostasis model assessment of insulin resistance values at the 6th month evaluation. There were no relationships between ADMA levels and age, sex, or pubertal state either before or during the treatment.Conclusion: Serum ADMA levels were found to be similar in patients with GHD and in healthy children. However, serum ADMA levels showed a significant increase in GHD patients following GH replacement therapy.     

Carbohydrate counting with an automated bolus calculator helps to improve glycaemic control in children with type 1 diabetes using multiple daily injection therapy: An 18-month observational study

Aims

This study aimed to investigate the effect of carbohydrate counting (carbC), with or without an automated bolus calculator (ABC), in children with type 1 diabetes treated with multiple daily insulin injections.

Methods

We evaluated 85 children, aged 9–16 years, with type 1 diabetes, divided into four groups: controls (n = 23), experienced carbC (n = 19), experienced carbC + ABC (n = 18) and non-experienced carbC + ABC (n = 25). Glycated haemoglobin (HbA1c), insulin use, and glycaemic variability – evaluated as high blood glucose index (HBGI) and low blood glucose index (LBGI) – were assessed at baseline and after 6 and 18 months.

Results

At baseline, age, disease duration, BMI, HbA1c, insulin use, and HBGI (but not LBGI; p = 0.020) were similar for all groups. After 6 months, HbA1c improved from baseline, although not significantly – patients using ABC (according to manufacturer's recommendations) HbA1c 7.14 ± 0.41% at 6 months vs. 7.35 ± 0.53% at baseline, (p = 0.136) or without carbC experience HbA1c 7.61 ± 0.62% vs. 7.95 ± 0.99% (p = 0.063). Patients using ABC had a better HBGI (p = 0.001) and a slightly worse LBGI (p = 0.010) than those not using ABC. ABC settings were then personalised. At 18 months, further improvements in HbA1c were seen in children using the ABC, especially in the non-experienced carbC group (−0.42% from baseline; p = 0.018).

Conclusions

CarbC helped to improve glycaemic control in children with type 1 diabetes using multiple daily injections. ABC use led to greater improvements in HbA1c, HBGI and LBGI compared with patients using only carbC, regardless of experience with carbC.     

Influencing factors of glycaemic control in patients attending different types of urban health care settings in Malaysia

The objective of this study was to elucidate influencing factors of HbA1C in various health care settings. The glycaemic control was suboptimal in all settings. Multivariate analysis confirmed three factors were significant in HbA1C outcome; insulin (p = 0.000), medication (p = 0.043) and ethnicity (p = 0.000).     

Glucoregulatory function among African Americans and European Americans with normal or pre-diabetic hemoglobin A1c levels

Objective

A hemoglobin (Hb) A1c range of 5.7%–6.4% has been recommended for the diagnosis of prediabetes. To determine the significance of such “prediabetic” HbA1c levels, we compared glucoregulatory function in persons with HbA1c levels of 5.7%–6.4% and those with HbA1c < 5.7%.

Methods

We studied 280 nondiabetic adults (142 black, 138 white; mean (± SD) age 44.2 ± 10.6 years). Each subject underwent clinical assessment, blood sampling for HbA1c measurement, and a 75-g oral glucose tolerance test at baseline. Additional assessments during subsequent outpatient visits included insulin sensitivity, using homeostasis model assessment (HOMA)-IR and the hyperinsulinemic euglycemic clamp; insulin secretion, using HOMA-B and frequently samples intravenous glucose tolerance test (FSIVGTT) and disposition index (DI); and measurement of fat mass, using DXA.

Results

Compared to subjects with HbA1c < 5.7%, persons with HbA1c levels of 5.7%–6.4% were older, and had higher body mass index (BMI) and insulin secretion but similar insulin sensitivity. When the two groups were matched in age and BMI, persons with HbA1c 5.7%–6.4% were indistinguishable from those with HbA1c < 5.7% with regard to all measures of glycemia and glucoregulatory function.

Conclusions

Unlike glucose-defined prediabetes status, an HbA1c range of 5.7%–6.4% does not reliably identify individuals with impaired insulin action or secretion, the classical defects underlying the pathophysiology of prediabetes. Thus, HbA1c cannot validly replace blood glucose measurement in the diagnosis of prediabetes. If utilized as a screening test due to convenience, aberrant HbA1c values should be corroborated with blood glucose measurement before therapeutic intervention.     

Plasma concentrations of arginine and asymmetric dimethylarginine do not reflect their intracellular concentrations in peripheral blood mononuclear cells

Objective

Production of nitric oxide (NO) from arginine is inhibited by endogenously produced monomethylarginine (MMA) and asymmetric dimethylarginine (ADMA). Elevated levels of ADMA, by limiting NO production, may lead to endothelial dysfunction and cardiovascular disease. Symmetric dimethylarginine (SDMA) and the arginine homolog homoarginine have also been associated with cardiovascular disease. Although NO synthesis, as well as generation of MMA, ADMA, SDMA and homoarginine, occurs intracellularly, these biomarkers are usually measured in plasma. Despite extensive transmembrane transport, it is not clear whether plasma levels of these biomarkers are a valid proxy for their intracellular levels in the cardiovascular system. Since it is difficult to obtain vascular tissue from healthy humans, we explored the relations between concentrations of these biomarkers in plasma and intracellular concentrations in peripheral blood mononuclear cells (PBMC).

Methods

In PBMC and plasma of 27 healthy subjects, concentrations of arginine, MMA, ADMA, SDMA, and homoarginine were determined using stable isotope dilution liquid chromatography tandem mass spectrometry.

Results

In PBMC, significant positive correlations were observed among arginine and its methylated forms (ρ = 0.43 to 0.81) and these correlations were slightly less pronounced in plasma. Homoarginine was not significantly correlated with (methylated) arginine in either PBMC or plasma. Plasma concentrations of arginine and its methylated forms showed non-significant inverse associations with their respective intracellular concentrations in PBMC and only for homoarginine was a weak positive association observed (ρ = 0.37).

Conclusion

In healthy individuals, plasma levels of arginine, MMA, ADMA, and SDMA poorly reflect their intracellular levels in PBMC.     

Oral, more than transdermal, oestrogen therapy lowers asymmetric dimethylarginine in healthy postmenopausal women: a randomized, placebo-controlled study

OBJECTIVE: To compare the effects of oral and transdermal hormone therapy (HT) on asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, in postmenopausal women. DESIGN: In a multicentre, placebo-controlled, double-blind study, 152 hysterectomized healthy women were randomized to receive daily transdermal 17beta-oestradiol (tE2, n = 33), or oral micronized 17beta-oestradiol either unopposed (oE2, n = 37), or continuous combined with gestodene (oE2 + G, n = 33), or placebo (n = 49) for 13, 28-day treatment cycles. Plasma concentrations of ADMA, arginine and symmetric dimethylarginine (SDMA) were measured at baseline and in treatment cycles 4 and 13 with a high-performance liquid chromatography method. RESULTS: After 13 cycles all active treatment groups showed a significant reduction in ADMA compared with placebo: tE2, -4.0% (95% CI: -7.5 to -0.6%); oE2, -7.7% (95% CI: -10.9 to -4.4%) and oE2 + G, -7.5% (95% CI: -10.8 to -4.3%). ancova showed a significantly larger reduction in the oral groups compared with the transdermal group (tE2 vs. oE2 and tE2 vs. oE2 + G, both P < 0.01). Oral, but not transdermal treatment, significantly reduced arginine compared with placebo. All active treatments reduced SDMA; however, this was only statistically significant in the oE2 group. CONCLUSION: Reduction of ADMA was more pronounced after oral than after tE2 administration. Adding gestodene to oral 17beta-oestradiol did not alter the reduction of ADMA. The clinical implications of these findings remain uncertain; however, the decrease of ADMA by 17beta-oestradiol could be a key phenomenon in the modulation of nitric oxide synthesis by postmenopausal HT.     

Incretin secretion is not restored by short-term strict glycaemic control in Korean hyperglycaemic patients with type 2 diabetes

Aims

To determine whether short-term strict glycaemic control could restore incretin secretion in type 2 diabetic patients. The factors associated with incretin levels were also investigated.

Methods

A meal tolerance test (MTT) was performed in eighteen poorly controlled (pDM) and fifteen well controlled (wDM) diabetic patients. Fourteen patients in the pDM group underwent follow-up MTT after strict glycaemic control. The secretions of intact glucagon-like peptide-1 (iGLP-1) and total glucose-dependent insulinotropic polypeptide (tGIP) during MTT were calculated by total and incremental area under the curve (TAUC and IAUC) values.

Results

Posttreatment HbA1c level was significantly improved in the pDM group (11.2 ± 0.9 to 7.9 ± 0.9%). However, the secretion of incretin hormones was not increased in the posttreatment pDM group (TAUCiGLP-1, 3612 ± 587 to 2916 ± 405 pmol/L min; TAUCtGIP, 9417 ± 1099 to 8338 ± 903 pmol/L min). IAUCiGLP-1 was negatively correlated (r = −0.446, P = 0.011) and independently associated (β = −137.2, P = 0.027) with insulin resistance assessed by homeostasis model assessment.

Conclusions

Incretin secretion is not restored by short-term strict glycaemic control. Decreased incretin secretion seems to develop early in the course of type 2 diabetes with increasing insulin resistance, but not to be influenced by glycaemic status.     

非对称性二甲基精氨酸和胱氨酸蛋白酶抑制剂C与冠心病

目的 探讨冠状动脉疾病中血浆非对称性二甲基精氨酸(ADMA)与胱氨酸蛋白酶抑制剂C(Cystatin C)之间的关系.方法 选取冠心病患者87例(其中急性心肌梗死39例,不稳定性心绞痛48例),健康对照组51例;同时,依据Cystatin C水平将冠心病患者分为Cystatin C升高组(51例)与无Cystatin C升高组(36例),采用高效液相色谱法测定血浆中ADMA、对称性二甲基精氨酸(SDMA)、左旋精氨酸(L-Arg)的含量,采用德国BNProSpec全自动速率散色比浊仪测定血浆Cystatin C的含量.结果 冠心病患者血浆ADMA[(0.47±0.15)μmol/L比(0.37±0.15)μmol/L]、SDMA[(0.39±0.19)μmol/L比(0.28±0.12)μmol/L]和Cystatin C浓度[(1.16±0.32)mg/L比(0.73±0.16)mg/L]均高于正常对照组(P均<0.05),L-Arg浓度低于正常对照组[(59.4±19.4)μmol/L比(83.7±19.6)μmol/L,P<0.05];对冠心病组的亚组分析显示血浆ADMA、L-Arg和Cystatin C浓度在心肌梗死组较心绞痛组差异无统计学意义.在Cystatin C<1 mg/L的冠心病患者中血浆ADMA与正常对照组比较,差异无统计学意义;而在Cystatin C>1 mg/L的冠心病患者血浆ADMA高于正常对照组[(0.50±0.17)μmol/L比(0.39±0.15)μmol/L,P<0.05].结论 只有在血浆Cystatin C水平升高的冠心病患者血浆ADMA水平才明显升高,提示冠心病患者血浆ADMA水平的升高并不与冠心病直接相关,可能与冠心病患者伴随轻微肾损害有关.     

Transjugular intrahepatic portosystemic shunt-placement increases arginine/asymmetric dimethylarginine ratio in cirrhotic patients

AIM：To analyze the change of dimethylarginine plasma levels in cirrhotic patients receiving transjugular intrahepatic portosystemic shunt（TIPS）.METHODS：To determine arginine,asymmetric dimethylarginine（ADMA）,symmetric dimethylarginine（SDMA）,and nitric oxide（NO） plasma levels,blood samples were collected from the superior cava,hepatic,and portal vein just before,directly after,and 3 mo after TIPS-placement.RESULTS：A significant increase in the arginine/ADMA ratio after TIPS placement was shown.Moreover,TIPS placement enhanced renal function and thereby decreased systemic SDMA levels.In patients with renal dysfunction before TIPS placement,both the arginine/ADMA ratio and creatinine clearance rate increased significantly,while this was not the case in patients with normal renal function before TIPS placement.Hepatic function did not change significantly after TIPS placement and no significant decline in ADMA plasma levels was measured.CONCLUSION：The increase of the arginine/ADMA ratio after TIPS placement suggests an increase in intracellular NO bioavailability.In addition,this study suggests that TIPS placement does not alter dimethylarginine dimethylaminohydrolase（DDAH） activity and confirms the major role of the liver as an ADMA clearing organ.